Mason is Huddersfield’s second experienced front-row recruit for next year following the capture of Warrington’s England international Chris Hill.
Huddersfield coach Ian Watson said: “He knows the club and he’s been here before.
“We’re proud of our young guys coming through but Nathan’s gone about it in a different way – he’s gone away and learned and now returns a better player. His desire to play and his desire to represent the Giants is a big plus for us.
“He’s coming back to us having developed into a guaranteed Super League player. Because he knows the club he’ll want to play for the shirt and that’s the kind of player we want to build the club on and have as an influence on those younger guys.
“Bringing Nathan Mason back will show players in the academy that even if you do go away, we’ll keep an eye on you and you can come back if you work hard.
“He’s developed physically and he’s a really big forward. He’s big, he’s got a change of pace. He’s able to put pressure on the half-back as well, which is important for those middles. He’s developed his game smarts as well, and he’s got strength and size.”
Mason said: “I’m excited to come back. There’s a lot of lads still here from when I was still here so it feels like coming back home.
“I’ve matured a fair bit, I’ve learned a whole lot and I’m coming in to prove a few people wrong.
“I’ve spoken with Ian Watson and Greg Brown and I’m excited to work with the two of them. It’s the first time I’ve worked with him, I’m really excited.”